The 502's

Levi's 502s were made
similar to the 501 jeans except that there was a zipper installed
instead of a button fly.
Characteristics are:

-Zip Fly
-Black bartack stitching at the top rear corners of the pockets
-'scovill' or 'gripper' zipper
-Redline inseam
-Big or small E red tab

These will fetch anywhere from 30.00USD up on Ebay. Expect at
least 60.00USD for Big E types as it designates the jeans as produced
before 1971.A patch listing the
style as 502-0117
Note the white in the lower left on
the hem. This is the
'Redline' selvedge, although
the faint redline that runs
through the white is often
faded. The white 'ears' of the
fabric are dead
giveaways for redlines.